Papers by Keyword: Optimal Control

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Authors: Marian Gaiceanu, Emil Rosu
Abstract: In this paper a voltage control strategy based on the optimal control theory, for isotropic rotor permanent magnet synchronous motor (PMSM) drives, is proposed. The complete optimal control of the three phase permanent magnet synchronous machine (PMSM) consists of three components: the state feedback, the feed forward compensation of the load torque and the reference to achieve the desired state. The control assures a smooth dynamic response, in order to achieve the desired state in steady state, the fast compensation of the load torque, and the energy minimization. The obtained solution by integrating the matrix Riccati differential equation (MRDE) is orientated towards the numerical implementation (by using a zero order hold) and it is computed on-line. The optimal control strategy is applied to PMSM drives and verified by simulations.
Authors: Li Li, Guo Qing Huang, Ming Xiang Yang, Min Yu
Abstract: This paper introduces design of a multimode controller for a Tactical Ballistic Missile autopilot that combined optimal control method with classical frequency domain analysis. In the paper, optimal control method is used to system structure design and to determine gain coefficient, frequency constraints in classical control theory are used to limit the weighting coefficient matrix of objective function in order to ensure system robustness. The simulation results show that the corresponding system responses have better quickness and some robustness, but the overshoot becomes a bit larger with contrast to traditional method.
Authors: Zhen Yu Han, Shu Rong Li
Abstract: This paper presents a numerical method based on quasilinearization and rationalized Haar functions for solving nonlinear optimal control problems including terminal state constraints, state and control inequality constraints. The optimal control problem is converted into a sequence of quadratic programming problems. The rationalized Haar functions with unknown coefficients are used to approximate the control variables and the derivative of the state variables. By adding artificial controls, the number of state and control variables is equal. Then the quasilinearization method is used to change the nonlinear optimal control problems with a sequence of constrained linear-quadratic optimal control problems. To show the effectiveness of the proposed method, the simulation results of two constrained nonlinear optimal control problems are presented.
Authors: Yang Shun, Li Da Zhang
Abstract: With the advance of electronic technology,the filed-oriented control of voltage space vector PWM have become more efficient in generator side converter control.This paper presented the direct driven wind turbine model and the permanent magnet synchronous generator (PMSG) model in synchronous rotating d-q reference frame.Using filed-oriented control of voltage space vector PWM in generator side converter control for enhance efficiency. The optimal control strategy can keep wind turbine working at optimal tip speed ratio for capture maximum wind power.A novel nonlinear PI controller for anti-windup implemented in control loop for highest efficiency of wind turbine which can be reached.Simulation results verified and shown via Matlab/Simulink that the performance of nonlinear PI controller for anti-windup in generator side converter control system is better than traditional PI controller in control loop for wind turbines.
Authors: Zheng Tao Yan, Hui Zheng, Xue Tao Weng, Cun Sheng Zhao
Abstract: Against the hybrid vibration isolation system process design problems, we proposed a hybrid optimization design method for vibration isolation system. Firstly, through investigating the rated operating characteristics of mechanical devices, we summarized the isolation devices effectiveness in the working band as an optimizing objective excitation function and extracted the multi-island algorithm advantage in multi-objective optimization field. Then using iSIGHT and Matlab to implement joint optimization, we got the optimal solution set of the passive vibration isolation parameters. Finally, we realized the system multi-objective control by the optimal control method, and achieved a better vibration isolation performance. This method puts forward a new idea for the succeeding hybrid vibration isolation system design effort.
Authors: Zdzisław Gosiewski, Maciej Henzel
Abstract: Highly maneuverable aircraft has redundant electrohydraulic actuators that generate the forces to drive the aircraft control surfaces. Two problems are important in these actuators. First, during reconfiguration of the actuator channels the hydraulic system works in the full range of its parameters. It leads to strongly nonlinear models of the redundant servo. Second, the frequency bandwidth of elements, which are located in the feedback loop of the servo, should be as wide as possible. Therefore, it is necessary to choose proper control method for actuator, where the controller of control system adjusts the set point signal. The advanced control methods can ensure the new quality of the systems. The new, advanced methods can cope with such problem in practical applications. There are available: adaptive methods, predictive methods, etc. and first of all, the robust control methods. These methods are robust on external disturbance. The causes of disturbances are very different: the inaccuracy in the mathematical and simulation model, the change of the operation point, the weather and temperature conditions, etc. We have designed such models in the Matlab/Simulink environment and we divided the full actuator into small subsystems.
Authors: Xiu Qin Yang, Kai Feng Zou
Abstract: In paper, the problem of robustify LQR for a class of uncertain linear systems is considered. An optimal controller is designed for the nominal system and an integral sliding surface is constructed. The ideal sliding motion can minimize a given quadratic performance index, and the reaching phase, which is inherent in conventional sliding mode control, is completely eliminated. Then the sliding mode control law is synthesized to guarantee the reachability of the specified sliding surface. The system dynamics is global robust to uncertainties which satisfy matching conditions. A GROSMC is realized. To verify the effectiveness of the proposed scheme, a robust optimal sliding mode controller is developed for rotor position control of an electrical servo drive system.
Authors: J.A. Fakharzadeh, F.N. Jafarpoor
Abstract: The mean idea of this paper is to present a new combinatorial solution technique for the controlled vibrating circle shell systems. Based on the classical results of the wave equations on circle domains, the trajectory is considered as a finite trigonometric series with unknown coefficients in polar coordinates. Then, the problem is transferred to one in which its unknowns are a positive Radon measure and some positive coefficients. Extending the underlying space helps us to prove the existence of the solution. By using the density properties and some approximation schemes, the problem is deformed into a finite linear programming and the nearly optimal trajectory and control are identified simultaneously. A numerical example is also given.
Authors: Chang Ji Shan, Jun Luo, Lin Li, Nan Xu, Yu Qiong Shan
Abstract: This paper is aimed to reach such a conclusion that the result gained from the analysis of the micro-vibration of coupled-pendulums made by optimal control theory is as consistent and effective as with that from other approaches, by the virtue of writing out the Lagrange equation of the micro-vibration of coupled-pendulums with the external force and analyzing the system by using control theories.
Authors: Guo Chun Sun, Li Meng He
Abstract: In this work, a new active mount featuring piezostack actuators and a rubber element is proposed and applied to a vibration control system. After describing the configuration and operating principle of the proposed mount, an appropriate rubber element and appropriate piezostacks are designed. Through the analysis of the property of the rubber and piezoelectric stack actuator, a mechanical model of the active vibration isolation system with the active mounts is established. An optimal control algorithm is presented for engine vibration isolation system. the controller is designed according to linear quadratic regulator (LQR) theory. Simulation shows the active system has a better consequence in reducing the vibration of the chassis significantly with respect to the ACM and the optimal control than that in the passive system.
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